How to solve message Waiting for tray 0 to lift with HP Laserjet printers

The message error Waiting for tray 0 to lift appears on these printers: HP CM6030, CP3525, CP4005, Laserjet 4000, 4200, 4250, 4350, 4700, 5500, 9040...
Paper is in the tray but no motors turn.


Solution 1:

• Turn the printer off. 
• Remove the Network Card. 
• Do a cold reset.
• Install the network card.

Solution 2:

• Download and install the latest firmware.

Solution 3:

• Take the paper out of the trays and check the trays mechanism, lift the tray by hand and make sure nothing is obstructing the movement or something broken.

Solution 4:

• Remove the toner.
• Lift the registration plate up.
• Check for torn pieces of paper blocking one of the sensors.